1. Field of Invention
This invention relates to a process for the production of molded particles for enzyme- or microbial cell-immobilization.
2. Description of Prior Arts
There have been known various methods to immobilize enzymes or microorganisms, such as encapsulation method, physical adsorption method and covalent bond method. Lump-like or sheet-like immobilized matters which are produced by these methods are usually cut or crushed fine before they are applied to enzyme reaction or microbial reaction. In these cases, however, immobilized matters often adhere to one another at the face, which decreases the efficiency of enzyme reaction or microbial reaction. On this account, it has recently been proposed to immobilize enzyme or microorganism cells in the form of molded particles so that they may have less contact area and therefore be readily flowable, and to thereby increase the efficiency of enzyme reaction or microbial reaction [e.g., Japanese Patent Publication No. Sho 62 (1987)-19837, Japanese Patent Application Laid-Open No. Hei 10 (1998)-210969].
Urethane resin which has conventionally been used for immobilizing enzyme or microorganisms has, however, photoreactive group(s) only at molecular terminals. Hence, when said photoreactive groups are subjected to photopolymerization reaction to render the urethane resin high-molecular, the resultant polymer molecules decreases both in the degree of unsaturated bond and in the number of crosslinking points, and thus fails to give molded particles with sufficient strength.
It is the primary objective of this invention to provide a process for the production of molded particles for enzyme- or microbial cell-immobilization which have good mechanical strength.
As a result of assiduous study in order to attain the above-mentioned objective, the inventors of this invention have now found out that, when a compound having one hydroxyl group and one epoxy group in a molecule is made to react with a compound having one carboxyl group and one ethylenically unsaturated group in a molecule, and when thus obtained unsaturated group-containing diol is further allowed to react with polyisocyanate compound, the resultant novel unsaturated group-containing urethane resin, when used as a constituent material for particulate carrier for immobilization, gives molded particles with remarkably much higher mechanical strength than the case where conventional urethane resin is used. The inventors have thus completed this invention.